• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.4
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• pp.161-167
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• 2013

Objectives: The objective of this study is compare the rate of marginal bone resorption around hydroxyapatite-coated implants given different loading times in order to evaluate their stability. Materials and Methods: The study was conducted retrospectively for one year, targeting 41 patients whose treatment areas were the posterior maxilla and the mandible. Osstem TS III HA (Osstem Implant Co., Busan, Korea) and Zimmer TSV-HA (Zimmer Dental, Carlsbad, CA, USA), which employ the new hydroxyapatite coating technique, were used. The patients were divided into two groups - immediate and delayed loading - and the bone level at the time of loading commencement and after one year of loading was measured using periapical radiography. Differences between the groups were evaluated using Mann-Whitney (${\alpha}$=0.05). Results: For all patients as a single group, the survival rate of the implants was 100%, and the mean marginal bone loss was $0.26{\pm}0.59mm$. In comparison of the differences by loading, mean marginal bone loss of $0.32{\pm}0.69mm$ was recorded for the immediate loading group whereas the delayed loading group had mean marginal bone loss of $0.16{\pm}0.42mm$. However, the difference was not significant (P>0.05). Conclusion: Within the limited observation period of one year, predictable survival rates can be expected when using immediately loaded hydroxyapatite-coated implants.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.2
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• pp.99-105
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• 2012

Purpose: The change of the marginal bone around dental implants have significance not only for the functional maintenance but also for the esthetic success of the implant. The purpose of this study was to investigate the load transfer of internal conical joint type implant according to marginal bone resorption by using the three-dimensional finite element analysis model. Materials and methods: The internal conical joint type system was selected as an experimental model. Finite element models of bone/implant/prosthesis complex were constructed. A load of 300 N was applied vertically beside 3 mm of implant axis. Results: The pattern of stress distribution according to marginal bone resorption was similar. The maximum equivalent stress of implant was increase according to marginal bone resorption and the largest maximum equivalent stress was shown at model of 1 mm marginal bone resorption. Although marginal bone loss more than 1mm was occurred increasing of stress, the width of the stress increase was decreasing. Conclusion: According to these results, the exposure of thin neck portion of internal conical joint type implant is most important factor in stress increasing.

• The Journal of Advanced Prosthodontics
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• v.14 no.2
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• pp.108-121
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• 2022

PURPOSE. The purpose of this study was to evaluate survival rates and marginal bone loss (MBL) of implants in IC-RPDs. MATERIALS AND METHODS. Seventy implants were placed and used as surveyed crowns in 30 RPDs. The survival rates and MBL around implants based on multiple variables, e.g., position, sex, age, opposing dentitions, splinting, type of used retainer, and first year bone loss, were analyzed. Patient reported outcome measures (PROMs) regarding functional/esthetic improvement after IC-RPD treatment, and complications were also inspected. RESULTS. The 100% implant survival rates were observed, and 60 of those implants showed MBL levels less than 1.5 mm. No significant differences in MBL of implants were observed between implant positions (maxilla vs. mandible; P = .341) and type of used retainers (P = .630). The implant MBL of greater than 0.5 mm at 1 year showed significantly higher MBL after that (P < .001). Splinted implant surveyed crowns showed lower MBL in the maxilla (splinted vs. non-splinted; P = .037). There were significant esthetic/functional improvements observed after treatment, but there were no significant differences in esthetic results based on implant position (maxilla vs. mandible). Implants in mandible showed significantly greater improvement in function than implants in the maxilla (P = .002). Prosthetic complication of IC-RPD was not observed frequently. However, 2 abutment teeth among 60 were failed. The bone loss of abutment teeth was lower than MBL of implants in IC-RPDs (P = .001). CONCLUSION. Class I RPD connected to residual teeth and strategically positioned implants as surveyed crowns can be a viable treatment modality.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.3
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• pp.70-80
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• 2010

This study proposes the algorithm to automate image alignment and detect marginal bone destructions, based on subtraction radiography for dental radiographic images necessary for dental PACS, which hasn't been covered by related literatures. The proposed algorithm enables a quick and precise detection of marginal bone destructions around teeth including implant through the knowlege-based multi-template matching in reference to ROI(Region Of Interest) obtained from applicable teeth using information about their geometric forms to solve problems single-template matching is exposed to. Actually, the test showed that it was possible not only to quickly and precisely detect marginal bone destructions around teeth, but also to get more objective and quantitative results through the algorithm.

• The Journal of Advanced Prosthodontics
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• v.8 no.5
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• pp.396-403
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• 2016

PURPOSE. Early loading of implant can be determined by excellent primary stability and characteristic of implant surface. The implant system with recently improved surface can have load application 4-6 weeks after installing in maxilla and mandible. This study evaluated the effect of healing period to the stability of hydrophilic tapered-type implant at maxillary posterior area. MATERIALS AND METHODS. This study included 30 patients treated by hydrophilic tapered-type implants (total 41 implants at maxilla) and classified by two groups depending on healing period. Group 1 (11 patients, 15 implants) was a control group and the healing period was 12 weeks, and Group 2 (19 patients, 26 implants) was test group and the healing period was 6 weeks. Immediately after implant placement, at the first impression taking, implant stability was measured using Osstell Mentor. The patients also took periapical radiographs after restoration delivery, 12 months after restoration and final followup period. The marginal bone loss around the implants was measured using the periapical radiographs. RESULTS. All implants were survived and success rate was 97.56%. The marginal bone loss was less than 1mm after 1 year postoperatively except the one implant. The stabilities of the implants were not correlated with age, healing period until loading, insertion torque (IT), the diameter of fixture and the location of implant. Only the quality of bone in group 2 (6 week) was correlated with the stability of implant. CONCLUSION. Healing period of 6 weeks can make the similar clinical prognosis of implants to that of healing period of 12 weeks if bone quality is carefully considered in case of early loading.

• The Journal of Advanced Prosthodontics
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• v.4 no.4
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• pp.210-217
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• 2012

PURPOSE. The purpose of this study was to analyze the current literatures and to assess outcomes of implant treatment in patients with generalized aggressive periodontitis. MATERIALS AND METHODS. Studies considered for inclusion were searched in Pub-Med. The literature search for studies published in English between 2000 and 2012 was performed. Our findings included literature assessing implant treatment in patients with a history of generalized aggressive periodontitis (GAP). All studies were screened according to inclusion criteria. The outcome measures were survival rate of superstructures, marginal bone loss around implant and survival rate of implants. All studies were divided into two follow-up period: short term study (< 5 years) and long term study (${\geq}5$ years). RESULTS. Seven prospective studies were selected, including four short-term and three long-term studies. The survival rates of the superstructures were generally high in patients with GAP, i.e. 95.9-100%. Marginal bone loss around implant in patients with GAP as compared with implants in patients with chronic periodontitis or periodontally healthy patients was not significantly greater in short term studies but was significantly greater in long term studies. In short term studies, the survival rates of implants were between 97.4% and 100% in patients with GAP-associated tooth loss, except one study. The survival rates of implants were between 83.3% and 96% in patients with GAP in long term studies. CONCLUSION. Implant treatment in patients with GAP is not contraindicated provided that adequate infection control and an individualized maintenance program are assured.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.169-174
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• 2008

Statement of problem: Changes of the marginal bone around dental implants have significance not only for the functional maintenance but also for the esthetic success of the implant. It was proposed that bone-retention elements such as microthreads at the coronal part of implant might help maintain the marginal bone level. Purpose: This study was designed to evaluate the effect of microthread configuration within the marginal coronal portion of the implant fixture at the marginal bone changes after loading around two different external hex implants. Material and methods: Twenty-four patients were included and randomly assigned to treatment with $Br{{\aa}}nemark$ system implants (Group 1, rough-surfaced implants, n=20) and Oneplant system implants (Group 2, rough-surfaced neck with microthreads, n=20). Clinical and radiographic examinations were conducted at baseline (implant loading) and 1 year postloading. Data analysis was performed by the SAS statistical package version 9.1.3 (SAS Institute, Cary, NC, USA) and the final model was calculated by the MIXED procedure (three-level ANCOVA) for marginal bone change of each test group at baseline and 1 year follow-up. Results: Comparing to baseline, significant differences were noted in marginal bone level changes for the 2 groups at 1 year follow-up (P<0.05). Group 1 had a mean crestal bone level changes of $0.83{\pm}0.31mm$; Group 2 had a mean crestal bone level changes of $0.44{\pm}0.36mm$. Rough-surfaced with microthreads implants showed significantly less marginal bone loss than rough surfaced neck without microthread implants. Conclusion: A rough surface with microthreads at the implant was beneficial design to maintain the marginal bone level against functional loading.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.4
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• pp.376-390
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• 2001

Alveolar bone changes after immediate loading on implants up to one year were observed by means of standard intraoral X-ray measurement which were taken at 3 month intervals. At the same time, bone density changes were observed according to digital subtraction method which is a becoming a more and more promising diagnostic tool for implants. Following results were obtained ; 1. There was no significant difference in the amount of alveolar bone loss implant type, sex and implant diameter, but there was difference according to case selection. In fully bone anchored prostheses cases, bone loss was $1.16{\pm}0.15m$ whereas, in partial edentulous cases, it was $1.84{\pm}0.08mm$. 2. Alveolar bone loss after immediate loading showed a higher degree of bone loss than after submerged loading in the initial three months. But there were no significant difference at the 12th month. 3. According to the one year bone density change observation at the alveolar bone surrounding the implant, significant change was observed vertically, whereas no significant change could observed horizontally. According to the above mentioned results, we can conclude that immediate loading of implants results in a higher degree of alveolar bone loss in one year than submerged loading. But since alveolar bone loss rate decreases to a reasonable rate after the initial 3 months of rapid bone loss, immediate loading of implants seems to be an acceptable treatment modality for patients with good bone conditions. Fully bone anchored cases showed an favorable outcome, but partial edentulous cases showed more bony resorption. So this cases considered in case selections. Bone density changes observation in the study was performed for only one year therefore a more longitudinal observation may be studied.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.135-142
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• 2008

Purpose: Numerous studies have shown that crestal bone resorption around the implant was related to the location of the implant abutment junction(IAJ). Recently it was hypothesized that platform switching termed the inward horizontal repositioning of the IAJ might limit bone resorption around the implants. The purpose of this clinical study was to evaluate the effect of platform switching on crestal bone resorption. Materials and Methods: The crestal bone loss of 65 external hex implants in 26 patients were radiographically measured at crown placement and follow-up examinations. 23 standard implants(non-platform switching group, NP) were connected with the matching abutments and 42 wide implants(platform switching group, PS) were connected with the 1 mm smaller diameter abutments. Results: There was significant difference of crestal bone loss between NP group and PS group. For implants in the NP group, mean crestal bone loss was $1.18{\pm}0.68\;mm$ at crown placement and $1.42{\pm}0.41\;mm$ at follow-up. The meal bone loss in PS group was $0.47{\pm}0.52\;mm$ at crown placement and $0.60{\pm}0.65\;mm$ at follow-up. When the crestal bone changes according to placement depths of implants were compared, subcrestal position of IAJ had a significantly less bone loss in PS group, but it was not in NP group. Conclusion: Within the limits of the present study, it was concluded that platform switching technique might decrease crestal bone loss around the implants. Additionally, when the IAJ of implant was placed 1 mm deeper in the alveolar bone, the effect of platform switching on bone loss was enhanced.

• Journal of Periodontal and Implant Science
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• v.38 no.3
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• pp.493-502
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• 2008

Purpose: The purpose of this study is to investigate on the regenerative capacity by using different size of graft materials around bony defect around implant. Material and Methods: Dental implant fixtures(Bio-TIS, Korea) were placed into the tibia of 8 rabbits. After placement of implant, artificial defects were created for each group, and the size of bone graft materials were used according to each designated group. 4 weeks after surgery, 8 rabbits were sacrificed. The histologic and histomorphometrical study were done for comparison of the regenerative capacity using $80-90{\mu}m$ and $200{\sim}1000{\mu}m$ size of grafting materials of OCS-$B^{(R)}$. Result: Matured bone formation was significantly increased more in Group E1($80-90{\mu}m$) than in Group E2($200{\sim}1000{\mu}m$). Group E1($80-90{\mu}m$) showed more significant augmentation in marginal length of graft material per unit area than Group E2($200{\sim}1000{\mu}m$). Group E1($80-90{\mu}m$) showed more interspace in graft material than Group E2($200{\sim}1000{\mu}m$). Control group showed no new bone formation around and inside of implanted fixture. Conclusion: Small grafting material size has great influence on bone regeneration.